Page 312 - IRSEM_Main Book

 Replace the signal lever under test and pull over each conflicting
point lever or combination of conflicting point levers in the route
separately and see if the signal lever is locked.

 Try each conflicting signal with the signal lever under test in the
normal position, pulling such levers as required releasing each
conflicting signal.

 Points in rear of the signal under test should be tried both in the
normal and reverse positions with the signal lever reversed to see
if the both ways locking is correct.

 The extent of this both ways locking in rear of each signal varies
according to local condition.

(iii) Junction Signal Test

(iv) In Figure 1, when lever No.2 is tested, it is not sufficient to pull 3 and
try if 4 is locked normal because 3 locks 4 both ways. The methods
of testing where the facing points stand normally unlocked, should be
as follows :-

 Try 1 and 2. Both should be locked.

 Pull 3 and try 1, 2 and 4, 2 and 4 should be locked and 1 free.

 Pull 1 and see that 3 is back locked.

 Replace all levers and pull 4 and 3, 1 should be locked, 4 locked in
reverse and 2 free.

 Pull 2 and see that 3 is back locked.

(v) Point Locking

(i) The locking between point levers is tested on the same principles as
the locking between signal levers, care being taken that each point
lever is free to be tested by pulling the releasing levers, if any, and also
that points are not being held by facing point locks.

Chapter 12: Installation, Testing & Maintenance of Mechanical Signalling Equipment Page 266 of 535